<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>eval</title>
		<script>
			var a=4,b=13;
			var str="alert(54)";
			eval(str);//alert(54)
			var c=eval("a+b");
			alert(c);
		</script>
	</head>
	<body>
	</body>
</html>
